A so called charging/discharging technique is generally becoming popular in which power is supplied from such a power supplying apparatus as a battery charger to a charging/discharging apparatus represented by a battery pack used in a video camera or the like to charge the same.
In such a battery pack, a time required for charging (a charging time) increases in accordance with increase in an allowable operation time of a battery, namely, increase in charging capacity of the battery. Therefore, in order to solve a problem that the allowable operation time of the battery should be increased, the charging time must also be increased correspondingly. On the contrary, in order to solve a problem that the charging time should be shortened, the allowable operation time must also be shortened. Thus, it has been impossible to solve these problems conflicting with each other.
In recent years, however, in order to solve these problems, a battery pack and a battery charger have been technically advanced so that it has been made possible to charge a battery pack using large current as a charging current from a battery charger. As a result, even when the charging capacity of a battery pack is made large, it has been made possible to shorten a time required for charging (high speed charging).
However, even when a user purchases such a battery pack technically advanced, it is a rare case that a conventional type battery pack (requiring a long charging time) is discarded, and the conventional battery pack is often used together with the newly purchased battery pack of a high speed charging type.
However, a new type battery charger is different in charging (power supplying) system from the conventional battery charger, and a charging current of the former is larger than that of the latter. For this reason, for example, when the conventional type battery pack is erroneously set to the new battery charger, it may be damaged due to an overcurrent.
Moreover, it is known that a proper temperature range applied for charging is set to each battery pack, and when charging the battery pack is repeated with a large charging current as described above under conditions out of the proper temperature range, the characteristic of each cell of the battery pack varies and the charging capacity thereof gradually decreases. Accordingly, there is a problem that, when charging of a battery pack is repeated under the conditions beyond the proper temperature range of the battery pack, the life of the battery pack is shortened.
The present invention has been made in view of these circumstances and its object is to make it possible to identify a charging system or a temperature condition of a battery pack to charge the battery pack in accordance with a corresponding proper charging system.